The long-term objective of this research is to explore human epididymal physiology and understand the process involved in the maturation of spermatozoa in man. The possible application to human health is in the field of treatment of infertility originating from epididymal failure, but may also provide supporting information for scientists interested in using epididymal antigens for fertility control. Specific aims include: 1) purification of epididymal secretory proteins that associate with spermatozoa, and development of specific antibodies against them. 2) Study of maturation parameters for human sperm, such as the ability to capacitate and suffer the acrosome reaction. 3) Determine the effect of the antibodies against epididymal proteins upon human sperm function. 4) Continue with a pilot study of a population of patients with unexplained infertility. 5) Purify hamster epididymal proteins and study their effect on the ability of immature sperm to bind to zona pellucida and fertilize eggs. 1) Usual protein purification procedures will be employed, purified proteins will be used as antigens to raise antibodies in rabbits and antisera used for localization studies. Purified proteins will be used for binding studies with spermatozoa from different segments. 2) Spermatozoa recovered from different epididymal segments will be incubated in conditions known to induce capacitation and acrosome reaction and their occurrence scored. Additionally, immature sperm will be exposed to epididymal proteins and changes in their function recorded. 3) Ejaculated human spermatozoa will be exposed to antisera raised against epididymal proteins and changes in their function examined. Entry of these immunoglobulins into the lumen of cultured human epididymal tubules will be assessed. 4) Patients with unexplained infertility are screened for a possible decrease in the amount of epididymal proteins attached to their ejaculated spermatozoa to identify a subpopulation of patient with epididymal failure that, at least potentially, can be relieved. Patients will be studied further in regard to sperm function and the possibility that such function can be modified by addition of exogenous epididymal protein. 5) Finally, the isolation and purification of hamster epididymal proteins and their effect on the function of immature spermatozoa will be studied.